I had purchased an LG 42LH30 in Nov during Fry's blowout sale.
My panel was produced in Oct 2009 in Mexico. My firmware originally was 4.31.01 - I could not access the technician menus to check on panel make. I definitely had a lipsync problem with my cable provider (FIOS Surewest) using HDMI using their HD box (ADB manufacturer) especially prominent with Dolby Digital audio selection on the cable box (less so with the PCM output setting on the box but still slightly present).
My TV was upgraded by technician to 4.34.01 using USB update - in retrospect the dolby digital output from HD box lipsync is still terrible. Back to PCM output where lipsync is less obvious.
At the suggestion of a previous poster on this thread I got an RCA RCR312W from Walmart. Entered the code suggested for TV selection - Now the "Guide" button brings me to the technician menu - unfortunately it only brings me to the menu that allows for panel determination, and WMA/JPEG options. It does not allow access to the lipsync menu. (the alternate technician menu)
I have unfortunately found out that my panel is an AUO 8bit panel.
FYI My specific make is 42LH30-UA.AUSDLUR